The history of Las Vegas is the ultimate American rags-to-riches story, filled with unusual heroes and foes. This 103-year-old saga follows the city through its incredible ups and downs, and highlights how and where some of the U.S.â€™s most monumental moments occurred. The largest American city founded in the 20th century took shape as a railroad watering hole before turning into the “Gateway to the Hoover Dam.” From there the town was known by its seedy mob label as â€œSin City,â€ before finally transforming into the corporately-financed adult playground called the “Entertainment Capital of the World.”